chore(deps): update plugin com.diffplug.spotless to v6.12.0 (#1406)

Author: nedtwigg

settings.gradle

@@ -1,6 +1,6 @@
 pluginManagement {
 	plugins {
-		id 'com.diffplug.spotless'                 version '6.11.0'
+		id 'com.diffplug.spotless'                 version '6.12.0'
 		// https://plugins.gradle.org/plugin/com.gradle.plugin-publish
 		id 'com.gradle.plugin-publish'             version '1.1.0'
 		// https://github.com/gradle-nexus/publish-plugin/releases